Colour Sensitivity of the Fovea Centralis

LAST year, one of us (E. N. W. 1 ) demonstrated that a small central area of the fovea was unable to discriminate blue-green colours and, in other ways also, appeared to have the characteristics of the tritanopic form of colour-blindness. The observations were made with small painted test spots suitably fixated on the foveal centre. The results aroused considerable interest and led to correspondence in Nature 2,3,4,5 , in which it was pointed out that König 6 , some fifty years ago, had noted that his foveal centre was tritanopic: his observation, however, did not appear to have been generally accepted 7 .